what you do. as long as the roots are warm you are good. can throw a large blanket onto the ground, around the plant at night lock the heat in . or throw more dirt around the base of the plant 2 or 3 feed wide. the ground stays warm a long time. the plant likes cooler during flowering. 55 is fine, on the plant, very dence buds. tight. buds, colorful I personally know people that drop the temp with ac low as possible too 60f. late flower. a tarp wont do shit. except fuck your plants up goes over the buds and there goes half your thc with it, wipes it off every time. and it still will be 55 under the tarp. only use a tarp with frost warnings, keeps frost off.